Merchants or other entities often outsource development of an electronic commerce presence on the Internet or other networks. These tasks can be outsourced to entities with expertise in development and management of an electronic presence. A merchant or other entity may wish to develop source code for generating user interfaces to be deployed on infrastructure maintained by another entity. However, the entity may not wish to grant access to the merchant to proprietary services that may be utilized to generate content or retrieve data for the layouts or user interfaces. Likewise, an entity may wish to outsource the development of layouts or user interfaces to be deployed on its infrastructure without granting access to its proprietary services as described above.